Jim Pasha's Alignment Specs OK for 17's?
11-21-2002, 09:08 PM
#1
Burning Brakes
Thread Starter
Jim Pasha's Alignment Specs OK for 17's?
Gang, I'm taking my '88 951 one in for an alignment tomorrow. I've had a few people verbally tell me what I should get. The problem is I can't remember what they told me and everyone has told me something different. Currently with the 996 17's with 205/50's in front and 255/40's in back the left rear is rubbing when ever the boost kicks in or when I hit a bad bump. It's driving me nuts.
I found an article written by Jim Pasha in which he suggest:
Front
3/4°, 1/16" toe in , 3° caster (as close as possible)
Rear
1° 1/16" toe in
Anyone running these specs with 17's? This car is a nights and weekend toy, but I never know when I might have to put it into daily service. I've never been to an autox or a DE. But would like to some day. No need for any fancy track settings.
Thanks,
I found an article written by Jim Pasha in which he suggest:
Front
3/4°, 1/16" toe in , 3° caster (as close as possible)
Rear
1° 1/16" toe in
Anyone running these specs with 17's? This car is a nights and weekend toy, but I never know when I might have to put it into daily service. I've never been to an autox or a DE. But would like to some day. No need for any fancy track settings.
Thanks,
11-21-2002, 10:02 PM
#3
RL Community Team
Rennlist Member
Rennlist Member
I have 17" 993 Cup Rims and I use those exact settings per Jim's recommendation and I think they're fine.
See this thread for a photo of me existing Turn 11 at Sears Point and you can see (well sorta see) the tire attitude while cornering.
<a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic&f=15&t=012330" target="_blank">http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic&f=15&t=012330</a>
Karl.
PS - An electronic copy of Jims article can be found at <a href="http://www.924.org/techsection/SuspensionPreparation.htm" target="_blank">http://www.924.org/techsection/SuspensionPreparation.htm</a>
See this thread for a photo of me existing Turn 11 at Sears Point and you can see (well sorta see) the tire attitude while cornering.
<a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic&f=15&t=012330" target="_blank">http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic&f=15&t=012330</a>
Karl.
PS - An electronic copy of Jims article can be found at <a href="http://www.924.org/techsection/SuspensionPreparation.htm" target="_blank">http://www.924.org/techsection/SuspensionPreparation.htm</a>
11-22-2002, 02:02 AM
#4
Race Director
Those specs sound fine, but I would make some minor adjustments.
Swap the front & rear camber so that you have -1 degree in front and -0.75 in the rear. This will reduce understeer and will match the roll-rates of the car better.
Increase the front caster to 3.5 degrees (close to max) to be at the high-end of the range recommended by the Porsche TSB on 17" wheels. This will reduce the tramlining effect frequently seen with 17" wheels (due to stiffer, shorter sidewalls).
So it comes out to:
FRONT
---------
-1.0° camber
3.5° caster
1/16" toe in
REAR
----------
-0.75° camber
1/16" toe in
Swap the front & rear camber so that you have -1 degree in front and -0.75 in the rear. This will reduce understeer and will match the roll-rates of the car better.
Increase the front caster to 3.5 degrees (close to max) to be at the high-end of the range recommended by the Porsche TSB on 17" wheels. This will reduce the tramlining effect frequently seen with 17" wheels (due to stiffer, shorter sidewalls).
So it comes out to:
FRONT
---------
-1.0° camber
3.5° caster
1/16" toe in
REAR
----------
-0.75° camber
1/16" toe in